The present invention relates to a method for increasing resolution in a compatible television system, such as described, for example, in European Pat. No. 57,826.A2.
The use of digital signal processing devices such as digital filters, digital real time memories, etc., in conjunction with offset transmission, offers the possibility of transmitting a television picture signal with significantly improved horizontal resolution and to reproduce it without edge flicker and with the same resolution in the direction of horizontal and vertical frequencies f.sup.x, f.sup.y in the spatial frequency domain.
The frequencies f.sup.x and f.sup.y define a frequency plane which relates to spatial frequencies for the modulation process. The f.sup.x -spectrum corresponds to the x-axis and the f.sup.y -spectrum to the y-axis relative to the two dimensional Fourier transform. X and y-axes correspond to the coordinates of the television picture to be processed.
The publications entitled "SMPTE, Winter Conference, Feb. 6-7, 1981, TV Technology in the 80's", pages 151-165, Scarsdale/N.Y., "ntz Archiv", Volume 4, 1982, No. 10, pages 293-301 and "ntz Archiv", Volume 4, 1982, No. 10, pages 303-312, describe measures for scanning pictures in conjunction with suitable filtering to assure improved horizontal resolution with the best possible assurance of compatility with existing standards.